This invention relates to a method and apparatus for producing and storing electrical energy at elevated temperatures by utilizing a porous bed of iron-iron oxide, which can be alternately oxidized and reduced, as the storage reservoir.
It has been proposed to utilize storage batteries to level the load on power plants over a given time period. Substantial economies are possible over power plants having no auxiliary load leveling means, since power plants normally experience about a 40% load variance over a typical 24 hour period. A large number of different battery systems have been proposed for this purpose, including lead-acid cells, nickel-iron cells, nickel-zinc cells, lithium-sulfur cells and zinc-chlorine systems. The lithium-sulfur and sodium-sulfur cells suffer from the disadvantages that the materials utilized are expensive and are highly corrosive. The other cells are disadvantageous because of their high cost.
The proposed system, by operating at elevated temperatures, can be more efficiently integrated into a power plant system than alternative storage batteries.